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Issued  June  7,  1913. 
Reprinted  without  change,  Jartjary,  1915. 


U.  S.  DEPARTMENT  OF  AGRICULTURE. 


FARMERS'   BULLETIN  535. 


SUGAR  AND  ITS  VALUE  AS  FOOD. 


BY 


MARY  HINMAN  ABEL. 


PREPARED  CNDER  THE  SUPERVISION  OP  THE  NUTRITION  INVESTIGATIONS. 
OFFICE  OP  EXPERIMENT  STATIONS. 


WASHINGTON: 
OOVKRNMENT  PRINTING  OFFICE. 

J9J5. 


Q?^(^ 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agricultube, 

.    Office  of  Experiment  Stations, 

Washington,  D.  C,  March  19,  1913. 

Sir  :  I  have  the  honor  to  transmit  herewith  an  article  on  sugar  and 
its  value  as  food,  prepared  by  Mrs.  Mary  Hinman  Abel,  who  has  made 
an  extended  study  of  the  subject,  taking  into  account  the  results  of 
laboratory  research- as  well  as  household  experience.  The  work  of 
the  Bureau  of  Chemistry  of  the  department  has  been  drawn  upon, 
and  also  the  results  of  nutrition  investigations  of  the  Office  of  Experi- 
ment Stations. 

Sugar  is  an  important  and  useful  foodstuff,  and  information  regard- 
ing it  is  very  commonly  requested  from  the  department.  It  is  be- 
lieved that  this  summary  of  available  information  concerning  sugar 
and  its  value  as  food  will  prove  useful  to  housekeepers  and  othei-s 
interested  in  the  subject. 

Tlie  bulletin  is  similar  in  its  general  character  to  other  farmers' 
bulletins  on  the  nature  and  use  of  food  materials  and,  like  them,  has 
been  prepared  under  the  general  supervision  of  C.  F.  Langworthy, 
chief  of  nutrition  investigations  of  the  Office  of  Experiment  Stations. 

In  its  present  form  this  bulletin  is  an  extension  and  revision  of  an 
earlier  farmers'  bulletin  (Farmers'  Bulletin  93,  "Sugar  as  Food"), 
which  it  is  designed  to  replace. 

A.  C.  True,  Director. 

lion  Datid  F.  Houston, 

Secretary  of  Agricyltwre. 

536 


CONTENTS. 


Page. 

Introduction 7 

Chemical  compoeition  of  eugare 7 

Characteristics  of  cane  sugar 8 

Characteristics  of  other  kinde  of  sugar 9 

Dextrose  and  levulose 9 

Milk  sugar 9 

Honey 10 

Japanese  ame 10 

Malt  sugars .    11 

Glycogen 11 

Sweet  materials  other  than  sugar 11 

Commercial  glucose  and  other  commercial  products  made  from  starch 11 

Sources  of  cane  sugar 12 

Sugar  from  the  sugar  cane 12 

Sugar  from  the  sugar  beet 13 

Sugar  from  the  sugar  maple 14 

Qiiality  of  sugar  from  different  sources 14 

Purity  of  sugar 16 

Food  value  of  sugar 16 

Digestion  of  sugar 17 

Sugar  as  a  food  for  muscular  work 17 

Sugar  as  a  fat  former 20 

Sugar  as  a  flavor 20 

Food  value  of  table  sirups  and  molasses 21 

Nutritive  value  of  sugar  cane 23 

Practical  use  of  sugar  in  the  ordinary  diet 23 

Amount  and  concentration 23 

Sugar  and  the  teeth 26 

Effect  of  exercise  on  the  amount  of  sugar  which  may  be  eaten 27 

Sugar  in  cooking,  preserving,  and  confectionery 27 

Sugar  in  fruita 29 

Sugar  in  the  dietaries  of  children 30 

Comparative  cost  of  sugar  aa  food 31 

General  conclusiona 31 

635  5 


SUGAR  AND  ITS  VALUE  AS  FOOD. 


INTRODUCTION. 

The  pleasant  flavor  of  sugar,  together  with  what  is  now  known  of 
its  nutritive  value,  wiQ  account  for  its  great  popularity  as  a  food.  It 
may  almost  be  said  that  people  eat  as  much  sugar  as  they  can  get, 
and  that  the  consumption  of  sugar  in  different  countries  is  in  general 
proportional  to  their  wealth. 

The  English-speaking  people  are  the  largest  consumers  of  sugar. 
In  1910  England  consumed  86.3  pounds  per  capita  and  the  United 
States  81.6  pounds,  although  stUl  larger  amounts  are  said  to  be  con- 
sumed in  sugar-growing  districts,  largely  in  the  form  of  the  ripe  cane. 
Denmark  that  year  consumed  77.7  pounds  per  capita;  Switzerland, 
64.3  pounds;  and  Germany,  France,  and  Holland  each  about  40 
pounds;  while  in  Italy,  Greece,  and  Servia  the  rate  was  only  about 
7  pounds  per  capita.  The  consumption  of  sugar  is  everywhere 
increasing. 

CHEMICAL  COMPOSITION  OF  SUGARS. 

The  term  "sugar,"  as  here  used  without  qualification,  means  the 
ordinary  sugar  of  commerce,  the  chemical  name  of  which  is  sucrose. 
Because  this  was  first  manufactured  from  sugar  cane  it  is  called  cane 
sugar,  but  the  same  sugar  is  manufactured  from  beets  and  is  known 
as  beet  sugar.  It  is  also  found  in  the  juice  of  many  other  plants. 
There  are  other  sugars  which  are  also  given  popular  names  denoting 
their  origin — ^for  instance,  mUk  sugar,  grape  sugar,  and  fruit  sugar. 
The  sugars  may  be  conveniently  divided  chemically  into  several 
groups  according  to  the  number  of  carbon  atoms  which  they  contain. 
The  most  important  from  the  standpoint  of  food  value  are  the  single 
sugars,  grape  sugar  (dextrose)  and  fruit  sugar  (Icvulose),  with  6  car- 
bon atoms;  and  the  double  sugars,  cane  sugar  (sucrose),  milk  sugar 
(lactose),  and  maltose  (malt  sugar),  in  which  the  molecule  contains  12 
carbon  atoms,  or  twice  as  many  as  in  the  single  sugars.* 

'The  brief  statement  of  the  chemical  nature  and  names  of  dilTerent  siigaro  and  other  carbohydrates 
which  follows  will  pcrhai)B  make  clear  to  hoiisekecpcrfi,  as  well  aw  to  othera  who  are  Interested  In  Hiich 
qutblUma,  tbla  interesting  part  of  the  chemlMlry  of  food. 

Cvbobydratea  are  oo  named  becaiine  they  are  composed  of  the  elements,  carljon,  hydrogen,  and  oxygen, 
the  hydrogen  and  oxygen  being  in  theBamoproi)orllonBa.sln  water,  which  incompotiodof  2atonmof  hydro- 
?€m  to  each  atom  of  oxygen.  '1  iiotigh  there  are  carl>ohydrat<)H  with  fewer  tlian  6  ami  with  more  than  6 
carlMn  aU^ma,  the  pirincipal  f^rliOhydralcH  used  as  food  contain  6  carbon  atoms  or  miilllpl<-«  of  0.    1'hese 

7 


8  SUGAE  AND  ITS  VALUE   AS  FOOD. 

By  a  chemical  process  called  inversion,  which  may  occur  in  different 
ways  (see  pp.  9  and  17),  one  molecule  of  the  double  sugar  is  made  to 
unite  with  water  and  form  two  molecules  of  single  sugar.  In  nature 
two  single  sugars,  dextrose  and  levulose,  often  occur  in  equal  pro- 
portions, and  the  combination  is  then  referred  to  as  invert  sugar. ' 

vSugar  belongs  to  the  important  gTOup  of  food  constituents,  car- 
bohydrates, so  named  because  as  a  whole  they  contain  the  element  | 
carbon  in  chemical  combination  with  oxygen  and  hydrogen,  these  ' 
two  elements  being  in  the  same  proportion  as  in  water.     Other  car- 
bohydrates closely  related  to  sugar  are  starch  and  crude  fiber,  or 
cellulose.     Sugars  and  starches  are  very  important  foodstuffs,  since  j 
with  fat  they  supply  the  bulk  of  the  energy  of  the  diet.     Crude  fiber,  ^ 
usually  digested  by  man  in  limited  quantities  only,  is,  nevertheless, 
an  important  foodstuff,  since  it  adds  bulk  to  the  diet. 

CHAUACTEIIISTICS  OP  CANE  SUGAR. 

Pure  cane  sugar  consists  of  a  mass  of  white  crystals  (e.  g.,  the  old 
fashioned  "rock  candy")  easily  soluble  in  about  haff  their  weight  of 
cold,  or  in  a  small  quantity  of  hot  water.  Cane  sugar  is  about  two 
and  one-half  times  as  sweet  as  grape  sugar. 

At  320°  F.,  considerably  above  the  boihng  point  of  water  (212°  F.), 
sugar  melts  into  a  colorless  liquid  which  rapidly  takes  on  an  amber 
hue.  If  it  is  then  cooled  quickly  it  hardens  into  a  glassy  mass, 
transparent  and  brittle,  which  is  called  "barley  sugar."  If  heated 
to  a  higher  temperature  it  browns,  becoming  less  sweet  and  acquiring 
a  somewhat  bitter  flavor.  This  browned  sugar  is  called  caramel. 
Old-fashioned  brown  sugar  owed  its  color  and  flavor,  at  least  partly, 
to  caramel,  for  the  process  of  manufacture  formerly  used  involved 
evaporation  over  an  open  fire,  which  caused  some  of  the  sugar  to 
become  carameHzed  or  haK  burnt,  since  in  the  final  stages  of  sugar 
making  the  mass  became  so  thick  that  it  could  not  move  about 
freely,  and  the  layer  next  to  the  bottom  of  the  kettle  was  raised  far 
above  the  boihng  point. 

are  (1)  monosaccharids  (single  sugars),  including  hexoses  (such  as  dextrose,  or  grape  sugar,  and  levulose, 
or  fruit  sugar),  so  called  because  the  molecule  contains  6  atoms  of  carbon  with  12  atoms  of  hydrogen  and 
6  atoms  of  oxygen;  (2)  disaccharids  (double  sugars,  such  as  cane  sugar,  and  lactose,  or  milk  sugar),  so  called 
because  the  molecule  contains  two  of  the  simple  sugar  molecules  less  one  molecule  of  water,  namely,  12 
atoms  of  carbon  with  22  of  hydrogen  and  11  of  oxygen;  and  (3)  polysaecharids  (such  as  starches),  so  called 
because  the  molecule  contains  repeated  many  times  the  simple  sugar  molecule  minus  the  molecule  of 
water  or  6  atords  of  carbon,  with  10  of  hydrogen  and  6  of  oxygen.  When  a  molecule  of  water  combines 
chemically  with  a  molecule  of  the  second  group,  two  hexose  molecules  are  formed,  and  when  the  neces- 
sary number  of  molecules  of  water  combine  chemically  with  a  molecule  of  the  thii'd  group,  two  or  more 
hexose  molecules  are  formed.  This  process,  called  inversion  or  hydrolysis,  may  occur  in  several  different 
ways. 

Each  group  of  sugars  contains  a  number  of  members;  for  example,  grape  sugar  and  fruit  sugar  have  the 
same  chemical  formula  and  the  same  percentage  of  carbon,  hydrogen,  and  oxygen,  although  they  are  not 
identical  substances.  The  difference  in  their  properties  is  due  to  different  groupings  of  the  atoms.  This 
must  not  be  confused  with  the  fact  that  the  same  sort  of  sugar  may  be  obtained  from  widely  different 
sources.  Thus  grape  sugar  is  found  in  grapes  and  other  fruits,  and  cane  sugar  is  foimd  in  the  juice  of  the 
sugar  cane,  beets,  carrots,  and  other  plants. 

535 


SUGAR  AND  ITS  VALUE   AS  FOOD.  9 

CK A R ACTEBISTIC S  OF  OTHER  KINDS  OP  SXTGAIL 
Dextrose  and  Levulose. 

/  Besides  cane  sugar,  the  commonest  kinds  are  dextrose  or  grape 
Bugar,  very  much  less  sweet  than  cane  sugar,  and  levulose,  very  much 
sweeter  than  dextrose.  These  two  sugars  are  usually  found  together. 
Dextrose  may  be  seen  in  yellowish  grains  in  the  raisin  and  other  sweet 
dried  fruits.  It  exists  in  small  quantities. in  many  fruits,  but  occurs 
chiefly  as  a  manufactured  product,  a  result  of  the  hydrolysis  of  starch, 
which  means  causing  it  to  unite  chemically  with  water  by  heating  it 
with  dilute  acids  or  in  some  other  way  to  induce  hydration.  By  this 
treatment  cane  sugar  is  split  up  into  a  mixture  of  dextrose  and  levulose 
known  as  ''invert "  sugar,  which  is  also  a  commercial  product.  Honey 
is  practically  a  natural  form  of  invert  sugar  in  which  there  is  usually 
more  levulose  than  dextrose. 

More  sugar  is  supposed  to  be  required  to  sweeten  acid  fruits  if  it  is 
added  before  cooking  than  if  it  is  added  afterwards,  and  this  is  ascribed 
to  the  change  of  the  cane  sugar  into  invert  sugar  under  the  influence 
of  the  acid  and  heat.  Aliss  Jennie  H.  Snow  ^  found  that  the  amount 
of  sugar  inverted  depends  upon  the  length  of  time  it  is  cooked  and  the 
degree  of  acidity,  and  her  conclusions  are  borne  out  by  the  results  of 
European  investigators.  She  found,  however,  that  loss  of  sweetness 
due  to  cooking  sugar  with  acid  fruit  is  so  slight  as  to  be  of  little  prac- 
tical consequence.  The  effect  of  heat  and  acids  in  "inverting"  cane 
sugar,  as  it  it  is  termed,  and  also  in  destroying  these  sugars,  has  to  be 
kept  in  view  constantly  in  the  manufacture  of  sugar.  By  the  slow 
methods  formerly  in  use  on  the  sugar  plantations,  the  juice  of  the 
cane  soured  before  it  was  boiled,  and  the  acids  so  formed  inverted 
much  of  the  cane  sugar  under  the  influence  of  heat.  /This  hindered 
crystallization,  as  did  also  the  caramel  produced  by  the  overheating 
of  a  portion  of  the  juice.  The  hindering  of  undesired  crystallization 
by  inversion  with  the  aid  of  a  little  aid  is  sometimes  very  important 
in  sugar  making.  Similarly,  manufacturers  of  candy  know  that  if 
they  wish  to  prevent  crystallization  or  ''graining'^  of  a  concentrated 
solution  of  sugar,  as  in  making  ** fondant"  or  soft  filling,  tartaric  or 
other  acid  must  be  added  to  invert  some  of  the  sugar. 

The  change  of  cane  sugar  in  solution  to  dextrose  and  levulose  men- 
tioned above  may  be  brought  about  even  in  the  absence  of  acid,  by 
the  action  of  heat,  or  by  certain  ferments,  such  as  invertase,  an 
enzym  of  yeast. 

Milk  Sugar. 

Milk  contains  from  4  to  5  per  cent  of  anotner  important  sugar — 
milk  sugar  or  lactose.     When  separated  and  purifled  it  is  a  crystalline 

•  Jour.  Horn.  Boon.,  1  (1908),  No.  3,  pp.  261  306. 
7OT23*— Bull.  .U'>— 1.5 2 


10  SUGAE  AND  ITS  VALUE  AS  FOOD. 

product  and  is  sold  in  that  form.  It  is  said  to  be  the  most  readily 
digestible  sugar  and  is  often  found  in  prepared  foods,  especially  those 
made  for  invalids  and  children.     It  is  much  less  sweet  than  cane  sugar. 

Honey. 

Before  sugar  was  a  common  commercial  product,  honey,  stored  by 
the  honeybee,  was  very  generally  used  to  sweeten  foods.  Although 
its  use  for  this  purpose  is  much  less  common  since  cane  sugar  has 
become  so  plentiful  and  cheap,  honey  is  still  highly  prized  as  a  whole- 
some sweet  food  and  is  used  either  alone  or  with  other  foods  in  a  great 
many  ways.  It  consists  of  a  natural  mixture  of  dextrose  and  levu- 
lose  (about  37  per  cent  of  each)  and  may  contain  as  high  as  6  to  8 
per  cent  of  sucrose.  An  average  analysk  shows  74.41  per  cent  of 
reducing  sugar  calculated  as  invert  sugar,  and  1 .98  per  cent  of  sucrose.* 
It  also  contains  an  average  of  17.59  per  cent  of  water  and  0.23  per 
cent  of  mineral  matter.  Its  flavor  is  due  to  volatile  bodies  in  the 
flowers  from  which  it  is  obtained,  some  flowers  imparting  a  more 
agreeable  flavor  than  others  to  the  honey.  It  was  formerly  assumed 
that  its  composition  was  practically  the  same  as  that  of  the  nectar 
gathered  by  the  bees,  but  recent  investigation  shows  that  the  nectar 
undergoes  certain  changes  in  the  honey  sack  of  the  bee,  and  that  the 
chemical  properties  of  honey  are  not  quite  like  those  of  the  nectar. 
Its  behavior  in  cooking  and  storing  is  different  from  that  of  the  ordi- 
nary sugars  for  reasons  not  yet  thoroughly  understood.  Honey  has 
been  used  as  a  food  from  the  earliest  times,  and  is  generally  conceded 
to  be  wholesome  as  well  as  palatable.  Prior  to  the  passage  of  the 
Federal  pure-food  law,  in  1906,  strained  honey  was  very  frequently 
adulterated  with  commercial  glucose  (see  p-  11)  and  other  materials, 
such  as  commercial  invert  sugar,  but  since  this  law  went  into  effect 
there  is  little  adulteration  of  this  product.  Mixtures  with  glucose 
and  invert  sugar  are  sold,  but  the  law  requires  that  they  be  so  labeled. 

Japanese  Ame. 

A  sweet  material  called  ame  has  been  made  in  Japan  since  early 
times  from  glutinous  rice  or  glutinous  millet,  sometimes  from  com- 
mon rice  and  rarely  from  Indian  corn  or  sweet  potatoes,  by  converting 
the  starch  they  contain  into  maltose  (a  double  sugar  similar  to  su- 
crose, lactose,  etc.)  by  the  action  of  an  unorganized  ferment  called 
diastase.  Malt  or  sprouted  barley  is  generally  used  to  furnish  the 
ferment.  The  cleaned  grain  or  other  material  is  soaked  in  water 
and  steamed  until  the  starch  grains  are  broken  open  and  made  easily 
accessible  to  the  ferment.  Powdered  malt  and  water  in  proper  pro- 
portions are  added,  and  in  six  or  eight  hours  the  diastase  converts 
the  starch  very  largely  into  dextrin  and  maltose.  The  liquid  is  then 
filtered  and  evaporated  to   the  desired  consistency,   which  varies 

1  U.  S.  Dept.  Agr.,  Bur.  Chem.  Bui.  110. 
535 


SUGAR  AND  ITS   VALUE  AS  FOOD.  11 

according  to  the  season.  One  of  the  forms  is  a  dense,  clear,  light- 
colored  amber  liquid  not  unlike  the  best  commercial  glucose  in  some 
of  its  physical  properties.  Another  form  is  hard  and  not  unlike  a 
white  candy  in  appearance.  Ame  has  been  manufactured  in  Japan 
for  at  least  two  thousand  years,  and  long  before  sugar  was  known  it 
was  a  favorite  flavoring.  Even  at  the  present  time  it  is  sometimes 
used  instead  of  sugar  in  cooking,  and  it  is  also  a  favorite  food  adjunct 
for  invalids. 

Malt  Sugars. 

Several  malt  preparations,  some  of  them  thick  like  sirup  and  others 
more  of  the  consistency  of  candy,  are  on  the  market.  These  are 
mixtures  of  dextrin  and  maltose  coming  from  the  action  of  diastase 
on  starchy  materials.  Many  commercial  products,  so-caUed  "pre- 
digested"  and  "malted"  products  and  similar  goods,  have  this 
material  as  their  basis. 

Glycogen. 

Glycogen  or  "animal  sugar"  is  a  carbohydrate  of  the  same  chem- 
ical composition  as  starch,  but  with  different  chemical  properties. 
It  is  found  in  smaU  amounts  in  muscular  tissue,  and  more  abundantly 
in  the  liver,  where  it  may  exist  in  considerable  quantities.  It  has 
an  important  function  in  nutrition,  being  stored  as  a  reserve  source 
of  energy  for  the  body. 

SWEET  MATEEIAIS  OTHER  THAN  SUGAR. 

Saccharin,  an  extremely  sweet  material,  is  not  a  sugar,  but  is  of 
an  entirely  different  chemical  structure,  boiag  a  benzene  compound. 
Its  use  in  food  products  was  forbidden  under  the  Federal  pure-food 
law,'  It  is  quite  commonly  prescribed  in  cases  of  diabetes  to  satisfy 
the  craving  for  sweets,  as  it  is  believed  to  be  less  harmful  in  such 
cases  than  the  sugar,  the  flavor  of  which  it  replaces. 

There  are  other  chemical  substances  which  are  not  sugars,  but 
which  have  a  marked  sweet  flavor.  They,  like  saccharin,  are  in  no 
sense  foodstuffs. 

COMMERCIAL  GLUCOSE  AND  OTHER  COMMERCIAL  PRODUCTS 
MADE  FROM  STARCH. 

"Commercial  glucose,"  "40  sugar,"  "80  sugar,"  and  "commercial 
ilcxtrose"  are  commercial  products  of  the  hydrolysis  of  starch.  The 
first  is  a  thick  liquid,  runJy  showing  crystallization,  havhig  a  coiii- 
position  of  between  30  and  39  per  cent  dextrose,  40  to  53  per  cent 
dextrin,  and  about  0.5  per  cent  ash.  The  others  are  solid  protlucts 
varying  in  percentag(5  of  <lextro80  up  to  95  per  cent,  with  small  quan- 
tities of  dextrin. 

I  U.  8.  I)ept.  Agr.,  Food  In«p.  Dnciiloni  13fi,  13R,  MO. 
S8fS 


12  STJGAE  AND  ITS  VALUE  AS  FOOD. 

Commercial  glucose  is  often  used  as  a  substitute  for  sugar  in 
sirups,  candy  making,  preserving,  etc.  Confectioners  maintain  that 
certain  kinds  of  candy  can  not  be  made  of  as  good  consistency  with 
pure  cane  sugar  as  with  the  addition  of  some  glucose.  In  such 
cases  it  can  hardly  be  considered  an  adulterant.  When  it  is  used 
as  a  cheaper  substitute  for  cane  sugar,  and  the  goods  are  sold  as 
cane-sugar  products,  its  use  is  evidently  fraudulent.  The  present 
law  in  the  United  States  requires  that  sirups,  jams,  jellies,  etc., 
made  with  glucose,  shall  be  so  labeled.  Its  nutritive  value  is  prac- 
tically the  same  as  that  of  other  carbohydrates,  and  there  is  no  reason 
to  suppose  that  when  properly  made  it  is  not  wholesome. 

SOUECES  OF  CANE  SUGAR. 

Cane  sugar,  beet  sugar,  sucrose,  or  simply  "sugar,"  as  it  is  known 
to  commerce  and  ia  the  household,  exists  ia  solution  in  many  vege- 
table juices.  It  is  found  in  the  stems  and  roots  of  the  grasses,  espe- 
cially in  the  sugar  cane,  sorghum,  and  cornstalks;  in  fleshy  roots,  as 
the  beet,  carrot,  turnip,  and  sweet  potato;  in  the  sap  of  trees,  as  the 
date  palm  and  sugar  maple;  in  almost  all  sweet  fruits;  and  in  the 
nectar  of  flowers.  Only  in  a  few  of  these,  however,  is  the  propor- 
tion of  cane  sugar  large  enough  to  make  profitable  its  separation 
from  the  other  substances  which  these  juices  hold  in  solution. 

In  fact,  the  cane  and  sugar  beet  are  the  only  important  sources  of 
sugar  (sucrose).  Of  the  world's  crop  of  16,418,500  tons  ia  1910-11, 
8,321,500  tons  were  made  from  cane,  and  8,097,000  from  the  bept. 

Sugar  is  a  staple  article  of  food,  just  as  is  bread  or  meat,  but  few 
reaUze  that,  unlike  bread  and  meat,  it  has  been  a  staple  food  for  but 
a  few  generations.  The  art  of  manufacturing  it  has  been  developed 
very  rapidly  within  the  last  125  years.  Only,  indeed,  in  the  last 
three-quarters  of  a  century  has  it  been  produced  in  such  quantities 
and  at  such  a  price  as  to  bring  it  into  reaUy  general  use. 

SUGAR  PROM  THE  SUGAR  CANE. 

The  sugar  cane  is  a  gigantic  joiated  grass  with  the  botanical  name 
Saccharum  officinarum,  native  to  eastern  India  and  China,  numerous 
varieties  of  which  are  now  grown  in  the  tropical  and  subtropical  regions 
of  both  hemispheres. 

Sugar  from  the  sugar  cane  was  probably  known  in  China  2,000 
years  before  it  was  used  in  Europe.  When  merchants  began  to  trade 
in  the  Indies,  sugar,  like  spices,  perfumes,  and  other  rare  and  costly 
merchandise,  was  brought  to  the  western  countries  of  Europe,  and  for 
a  long  time  it  was  used  exclusively  in  the  preparation  of  medicines. 
An  old  saying  to  express  the  lack  of  something  very  essential  was 
**Like  an  apothecary  without  sugar."  Several  centuries  before  the 
Christian  Era  Greek  physicians  knew  of  sugar  under  the  name  of 
"Indian  salt."     It  was  also  called  "honey  made  from  reeds,"  and  was 

535 


SUGAR  AND  ITS   VALUE   AS  FOOD.  13 

said  to  be  "like  giim,  white  and  brittle."  But  not  until  the  Middle 
Ages  did  Europeans  have  any  clear  idea  of  its  origin.  It  was  con- 
founded with  manna  or  was  thought  to  exude  from  the  stem  of  a 
plant,  where  it  dried  mto  a  kuid  of  gum.  Wlien  in  the  fourteenth  or 
fifteenth  century  the  sugar  cane  from  India  was  cultivated  in  northern 
Africa,  the  use  of  sugar  greatly  increased,  and  as  its  culture  was 
extended  to  the  newly-discovered  Canary  Islands  and  later  to  the 
West  Indies  and  Brazil,  it  became  a  common  article  of  food  among  the 
well-to-do.  By  many  the  new  food  was  still  regarded  with  suspicion. 
It  was  said  to  be  very  heating,  to  be  bad  for  the  lungs,  and  even  to 
cause  appoplexy.  Honey  was  thought  to  be  more  wholesome,  because 
more  natural  than  the  "products  of  forced  invention."  The  sugar- 
growing  industry  in  what  is  now  the  United  States  dates  from  1751. 
It  has  developed  into  a  great  enterprise,  as  has  also  sugar  refining. 

SUGAB  FROM  THE  SUGAR  BEET. 

The  sugar  consumed  in  this  and  other  countries  up  to  1850  was 
nearly  all  derived  from  the  sugar  cane,  but  at  the  present  time  one- 
half  of  the  sugar  crop  is  obtained  from  the  sugar  beet.  Between  1863 
and  1883  Germany,  one  of  the  leading  beet-sugar  producing  coun- 
tries, increased  its  output  338  per  cent.  It  would  once  have  seemed 
incredible  that  the  kitchen  garden  should  furnish  a  rival  for  the 
"noble  plant"  that  had  made  the  fortunes  of  Spanish  and  English 
colonies,  but  the  cultivation  of  the  beet  for  sugar  has  in  one  generation 
shifted  the  center  of  the  sugar  industry  from  the  Tropics  to  the 
Temperate  Zone.  This  growth  has  been  fostered  by  strange  vicissi- 
tudes in  the  fortunes  of  nations,  such  as  the  commercial  embargoes 
and  sugar  bounties  of  the  Napoleonic  wars,  and  the  abolition  of 
slavery  in  the  British  colonies,  giving,  as  it  did,  a  temporary  check  to 
the  growth  of  the  cane,  aided  in  the  creation  of  the  beet-sugar  indus- 
try. The  real  creators  of  the  new  industry,  however,  were  men  of 
scientific  training  who  solved  certain  botanical  and  chemical  problems. 

In  1747  Marggraf,  a  chemist  of  Berlin,  discovered  that  beets  and 
other  fleshy  roots  contain  a  crystallizable  sugar  identical  with  that  of 
the  sugar  cane.  In  1799  the  subject  was  brought  before  the  French 
Academy,  and  in  1801  the  first  manufactory  for  beet  sugar  was 
erected.  It  had  been  manufactured  as  early  as  1797,  but  the  2  or  3 
per  cent  of  sugar  tiiat  could  bo  extracted  by  the  methods  then  in  use 
was  too  little  for  commercial  success.  A  now  stimulus  was  given  by 
the  sugar  bounties  of  Napoleon  in  1806,  and  methods  improved 
ra[)idly,  especially  in  Franco.  Two  grcnit  diffif^ulties  still  roniained: 
The  percentage  of  sugar  present  in  the  beet  was  siriall  (6  per  cent), 
and  it  was  oiUy  with  groat  difliculty  that  it  could  be  separated  from 
tlie  many  otluT  constituents,  some  of  them  acrid  and  having  a  very 
unpl«;usunt  flavor.  Sci(;nco  now  came  to  the  aid  of  the  industry,  and 
a  beet  was  gradually  developed  with  a  larger  percentage  of  sugar  and 

535 


14  SUGAE  AND  ITS  VALUE  AS  EOOD. 

a  smaller  percentage  of  the  undesirable  impurities.  Eighteen  tons 
of  beet  roots  were  necessary  in  1836  to  produce  1  ton  of  sugai ;  in 
1850,  this  quantity  was  reduced  to  13.8  tons;  in  1860,  to  12.7  tons,  and 
in  1889,  to  9.25  tons.  From  5  per  cent  of  sugar,  as  found  by  Marggraf , 
the  sugar  beet  of  good  quality,  thanks  to  the  scientific  work  which 
has  developed  it,  now  contains  15  per  cent  and  more,  at  least  12  per 
cent  being  considered  necessary  for  profitable  manufacture. 

SUGAR  FROM  THE  SUGAR  MAPLE. 

The  sugar  maple  of  North  America  is  also  a  source  of  sucrose,  the 
trees  being  tapped  in  the  early  spring  to  obtain  the  sap  as  it  flows 
upward  through  the  trunk  on  the  way  to  the  branches.  This  sap 
on  boiling  yields  its  2.5  per  cent  of  sucrose  and  a  few  nonsugarsin  a 
more  or  less  moist,  brown,  crystalUne  mass,  which  can  be  refined 
until  it  is  like  other  pure  sucrose.  However,  on  account  of  the  pleas- 
ant flavor  the  product  in  its  crude  form  sells  for  a  better  price  than 
would  the  refined  sugar.  Five  gallons  of  sap  yield  about  a  pound  of 
sugar.  Equally  popular  is  the  maple  sirup;  that  is,  the  sap  which 
has  been  boiled  down,  but  not  enough  to  crystallize. 

It  is  said,  apparently  on  good  authority,  that  maple  sugar  was 
made  by  the  American  Indians  for  an  untold  time  before  Europeans 
came  to  this  continent.  It  is  interesting  to  read  a  paragraph  from  a 
book  written  by  the  eminent  Robert  Boyle  and  printed  at  Oxford  in 
1663: 

There  is  in  some  parte  of  New  England  a  kind  of  tree  *  *  *  whose  juice  that 
weeps  out  of  its  incisions,  if  it  be  permitted  slowly  to  exhale  away  the  superfluous 
moisture,  doth  congeal  into  a  sweet  and  saccharin  substance,  and  the  like  was  con- 
firmed to  me  by  the  agent  of  the  great  and  populous  colony  of  Massachusetts. 

Maple  sugar  was  also  appreciated  in  colonial  times  for  making 
sweets  as  well  as  for  use  as  a  staple  article  of  diet,  for  early  records 
mention  a  "nut  sweet"  made  from  maple  sugar,  butter,  and  nuts, 
the  sugar  being  melted  and  slightly  browned  in  order  to  impart  a 
caramel  flavor  in  addition  to  the  maple  flavor. 

Occasionally,  by  a  method  similar  to  that  by  which  maple  sugar  is 
obtained,  sugar  is  made,  or  was  made  in  colonial  times,  from  the  sap 
of  the  butternut  tree,  and,  it  is  said,  from  the  birch  also. 

According  to  the  Preliminary  Report  of  the  United  States  Census 
for  1910,  the  total  quantity  of  maple  sugar  produced  in  tliis  country 
in  1909  was  14,060,206  pounds  and  the  total  amount  of  maple  sirup 
was  4,106,418  gallons. 

QUALITY  OF  SUGAR  FROM  DIFFERENT  SOURCES. 

The  methods  used  in  the  manufacture  of  sugar  are  all  devised  to 
separate  the  sugar  from  the  other  constituents  of  the  juice.  The 
juice  containing  the  sugar  is  expressed  or  extracted  from  the  cane^ 

535 


SUGAR  AND  ITS  VALUE  AS  FOOD. 


15 


beet,  etc.,  treated  to  remove  the  nonsaccharin  substances  which 
prevent  crystallization,  and  evaporated  in  vacuum  apparatus  to  pre- 
vent burning;  the  sugar  is  then  crystallized,  and  the  crystals  sepa- 
rated from  the  molasses  in  centrifugals.  Modified  methods  of  man- 
ufacture may  produce  white  granulated  sugar  direct  from  the  beet 
or  the  cane.  When  these  are  not  used,  the  product  is  "raw  sugar" 
which  must  be  passed  through  some  refining  process  before  it  is 
white  sugar.  The  methods  of  manufacturing  sugar  from  the  beet 
are  described  in  a  pre\dous  bulletin  of  this  series.* 

The  average  composition  of  raw  sugar  from  a  number  of  different 
sources  is  as  follows: 

Average  composition  of  raw  sugar. 


Sugar  from- 


other 

Water 

Cane 

organic 

sugar. 

sub- 
stances. 

Per  cent. 

Percent. 

Percent. 

2.16 

93.33 

4.24 

2.90 

92.90 

2.59 

2.50 

88.42 

7.62 

1.86 

87.97 

9.65 

7.50 

82.80 

8.79 

Ash. 


Sugarcane 
Sugar  beet 

Uaize 

Palm 

Maple 


Percent. 

1.27 

2.56 

1.47 

.50 

.91 


Raw  sugar  from  these  various  sources  takes  on  in  each  case  the 
character  of  the  impurities  from  which  it  has  not  yet  been  freed. 
Thus,  the  raw  products  of  the  sugar  cane,  maize,  and  the  sugar 
maple,  are  pleasant  in  flavor,  that  of  the  beet  is  acrid  and  disagree- 
able, while  the  raw  palm  sugar  or  jaggary  is  of   low  sweetening 
power,  because  of  the  lai^e  amount  of  invert  sugar  (dextrose  and 
levulose,  see  p.  9)  that   has   resulted   from   fermentation  and  too 
high   a  degree  of  heat  used  in  evaporation.     From  all  these  raw 
sugars  the  pure  cane  sugar,  or  sucrose,  as  known  to  the  chemist, 
can  be  crystallized  out,  and  in  every  case  the  sugar  is  identical  in 
chemical  composition,  appearance,  and  properties.     By  no  chemical 
t^'Ht  can  the  pure  crystallized  sugar  from  these  different  sources  be 
distinguished.     There  is  a  popular  impression  to  the  contrary,  how- 
ever, and  it  is  often  asserted  that  beet  sugar  luis  less  sweetening 
power,  or  that  fruits  preserved  with  it  do  not  keep  us  well,  but  this 
can  be  true  only  of  specimens  that  have  been  imperfectly  purified. 
Tests  made  at  the  California  Experiment  Station '  led  to  the  coii- 
lijsion  that  the  two  sorts  of  sugar  were  equally  valuable  for  can- 
ing, and  identical  In  their  behavior  when  of  the  same  fineness  of 
ystallization. 

Methods  of  refining  raw  sugar  have  been  so  improved  in  the  hist 
f<:w  years  that  it  may  bo  truly  said  tliat  f(!W  food  substances  are  ho 
nearly  pure  chemically  as  the  best  granulated  or  hmip  sugar. 


>  U.  8.  Dept.  Agr.,  Farmen'  Ilul.  62. 


>  ealifornia  SU.  (ire.  .3S. 


»8fi 


16  SUGAK  AND  ITS  VALUE  AS  FOOD. 

PURITY  OF  SUGAE. 

Of  500  samples  of  sugar  examined  several  years  ago  by  the  Bureau 
of  Chemistry  of  this  department/  not  one  was  found  to  be  adulterated. 
The  low  price  of  cane  sugar,  in  comparison  with  the  price  of  substances 
that  might  be  used  for  adulteration,  protects  it  from  such  attempts. 

A  more  recent  publication  of  the  Bureau  of  Chemistry  ^  states 
that  sugars  as  a  class,  both  the  high  and  low  grades  as  now  found 
on  the  market,  are  practically  free  from  adulteration.  This  is  par- 
ticularly true  since  the  Federal  pure-food  law  of  1906  went  into  effect. 

There  is  a  popular  belief  that  granulated  sugar  is  often  adulterated 
with  white  sand  or  finely  ground  rock,  and  that  pulverized  sugar  is 
commonly  adulterated  with  starch  or  lime  dust.  Cases  of  such 
adulteration,  however,  have  rarely  been  found  by  the  Bureau  of 
Chemistry,  though  starch  has  been  detected  in  a  very  few  samples 
of  powdered  sugar.  It  is  a  very  simple  matter  to  test  suspicious 
sugar  for  the  presence  of  such  materials.  Sugar  is  readily  soluble 
in  water,  and  the  sand  and  mineral  adulterants  are  insoluble.  If  a 
spoonful  of  sugar  is  added  to  a  glass  of  water  and  stbred,  it  will  com- 
pletely dissolve,  while  any  sand  or  similar  material  will  remain  un- 
dissolved. If  the  water  is  warm  the  sugar  will  dissolve  more  quickly 
than  otherwise,  and  care  must  be  taken  to  continue  the  stirring 
for  considerable  time,  as  some  of  the  very  dry  crystallme  sugars 
dissolve  rather  slowly. 

FOOD  VALUE  OF  SUGAR. 

The  most  interesting  use  of  sugar  is  as  a  food  for  the  animal  body. 
Within  certain  limits,  sugar  may  be  considered  as  the  equivalent  of 
starch  that  has  been  digested  and  made  ready  for  absorption.  A 
mealy  boiled  potato,  like  all  forms  of  starchy  food,  must  be  largely 
converted  into  some  kind  of  sugar  by  the  digestive  juices  before  it 
can  be  absorbed  as  food. 

It  is  commonly  stated  that  the  food  eaten  by  the  average  adult  is 
at  least  one-half  of  vegetable  origin,  and  analyses  show  that  the 
nutrients  of  vegetable  foods  are  very  largely  starch.  The  average  of 
400  dietary  studies  made  in  the  United  States  shows  about  40  per 
cent  animal  food  and  60  per  cent  vegetable  food.  Starch  in  cereal 
grains  and  other  foods,  and  separated  as  cornstarch,  etc.,  furnishes 
a  considerable  part  of  the  heat  and  muscular  power  of  the  body.  The 
summary  of  data  regarding  the  American  diet  quoted  above  shows 
that  sugar  constitutes  5.4  per  cent  of  the  average  diet  and  furnishes 
17.5  per  cent  of  the  total  energy  in  it.  It  is  clear  that  starch,  sugar, 
or  any  food  that  will  serve  the  same  purpose  is  of  great  importance. 

To  understand  the  utilization  of  such  foods  ia  the  body  better,  the 
process   of  carbohydrate   digestion  may  be   considered.     When  a 

»  U.  S.  Dept.  Agr.,  Div.  Chem.  Bui,  13,  pt.  6.  a  U.  S.  Dept.  Agr.,  Bur.  Chem.  Bid.  100. 

535 


SUGAR  AND  ITS  VALUE   AS  FOOD.  17 

starchy  food,  such  as  boiled  potato,  is  taken  into  the  month,  it  is 
at  once  acted  upon  more  or  less  by  a  ferment  contained  in  the  saliva, 
and  this  action  is  continued  by  a  ferment  contained  in  the  intestines. 
It  is  broken  up  into  simpler  chemical  compounds,  and  it  finally 
reaches  the  blood  and  muscles  as  dextrose,  a  form  of  sugar  which  can 
be  burned  in  the  body  to  yield  muscular  energy  and  heat.  "When  an 
excess  of  carbohydrates  (sugar  or  starch)  is  consumed,  the  dextrose 
in  the  digestive  tract  is  converted  in  the-  liver  to  glycogen  and  stored 
until  required,  being  then,  it  is  believed,  reconverted  into  dextrose. 
More  complex  changes  may  take  place  which  convert  carbohydrates 
consumed  in  excess  into  fat,  wliich  is  also  stored  as  a  reserve  material. 
Some  recent  German  investigations  indicate  that  the  different 
kinds  of  sugar  are  not  equally  well  adapted  to  increasing  the  supply 
of  glycogen  in  the  body.  In  experiments  with  dogs,  sucrose  and 
dextrose  proved  the  most  valuable  in  this  respect. 

DIGESTION  OF  SUGAR. 

When  sugar  is  eaten  it  is  changed  in  the  digestive  tract  before  it 
is  taken  up  in  the  blood  and  carried  where  it  is  needed.  If  a  solution 
of  cane  sugar  be  injected  directly  into  the  blood,  it  is  passed  out  by 
the  kidneys  unchanged,  showing  that  it  is  not  fitted  for  assimilation 
until  it  has  been  changed,  as  it  is  in  normal  digestion.  The  change 
needed  is  slight  compared  with  that  required  for  the  digestion  of 
starch,  sugar  being  "inverted"  or  changed  into  the  simpler  sugars 
as  already  described  (see  p.  9),  and  this  change  is  brought  about 
in  the  digestive  tract  by  the  agency  of  enzyms  or  ferments  regard- 
ing the  nature  of  which  little  is  known.  When  thus  changed  into 
the  simpler  sugars,  its  function  in  the  body  is  similar  to  that  of 
starch  after  it  has  reached  the  analogous  stage  in  digestion. 

At  the  Minnesota  Experiment  Station^  the  thorouglmess  of  diges- 
tion of  sugar  was  studied  with  healthy  men,  5  ounces  per  day  being 
consumed  as  part  of  a  simple  mixed  diet.  The  sugar  showed  a  high 
digastibility,  98.9  per  cent  of  its  total  energy  being  available  to  the 
body,  on  the  average.  In  general,  it  increased  the  available  energy 
of  the  whole  ration  25  per  cent  and  did  not  aflFect  the  digestibility 
of  the  foods  with  which  it  was  combined.  Tho  protein  of  the  ration 
was  more  economically  used  than  commonly,  the  nitrogen  retention 
being  increased  25  per  cent.  It  was  pointed  out  in  discussing  these 
experiments  that  "the  value  of  sugar  in  a  ration  depends  upon  its 
judicious  use  and  combination  with  otlier  foods." 

SUGAR  AS  A  FOOD  FOR  MUSCULAR  WORK. 

Food  must  supply  enough  protein  or  nitrogenous  material  for  the 
formation  and  ro[)air  of  tissues  and  for  c(U'tain  other  uses  in  tlio  body, 
and  in  addition  suflicient  oth(»r  material  to  make  up  the  amount  of 

>  HlnnoMta  Bta.  Rpt.  190S-4. 
6.^5 


18  SUGAE  AND   ITS   VALUE   AS   FOOD, 

energy  necessary  for  heat  and  muscular  work.  The  nitrogen-free 
nutrients  are  fats  and  carbohydrates.  In  the  ordinary  diet  the  rela- 
tive amount  of  fat  and  carbohydrates,  is  usually  regulated  by  per- 
sonal preference.  Fat  will  furnish  two  and  one-fourth  times  as  much 
energy  per  pound  as  carbohydrates.  Taking  account  of  this  fact  it 
is  immaterial  on  chemical  grounds  which  of  these  nutrients  supplies 
the  necessary  energy,  although  this  is  not  the  case  from  the  stand- 
point of  hygiene. 

The  main  function  of  sugar  as  found  in  the  blood,  whether  result- 
ing from  the  digestion  of  sugar  or  of  starch,  is  believed  to  be  the 
production  of  energy  for  internal  and  external  muscular  work,  and, 
as  a  necessary  accompaniment,  body  heat.  This  has  been  amply 
demonstrated  by  experiment.  By  ingenious  devices  the  blood  going 
to  and  from  a  muscle  of  a  living  animal  may  be  analyzed,  and  it  is  thus 
shown  that  more  blood  traverses  an  active  or  working  muscle  and 
more  sugar  disappears  from  it  than  is  the  case  with  a  muscle  at  rest. 

To  decide  the  question  of  the  value  of  sugar  as  a  source  of  energy 
for  the  working  muscle,  much  careful  laboratory  work  has  been  car- 
ried on.  It  has  been  found  that  an  increase  in  the  sugar  content  of 
the  diet,  when  not  too  great  and  when  the  sugar  is  not  too  concen- 
trated, lessens  or  delays  fatigue  and  increases  working  power.  In- 
creased amounts  of  sugar  were  found  to  increase  the  ability  to  perform 
muscular  work  to  such  an  extent  that  on  a  ration  of  500  grams  (17.5 
ounces)  of  sugar  alone  a  man  was  able  to  do  61  to  76  per  cent  more 
work  than  on  a  fasting  diet,  or  almost  as  much  as  on  a  full  ordinary 
diet.  The  addition  of  about  half  this  quantity  of  sugar  to  an  ordi- 
nary or  to  a  meager  diet  also  considerably  increased  the  capacity  for 
work,  the  effect  of  the  sugar  being  felt  about  a  half  hour  after  eating 
it,  and  its  maximum  effect  showing  itself  about  two  hours  after 
eating.  The  coming  of  fatigue  was  also  found  to  be  considerajbly 
delayed  on  this  diet,  and  taking  3  or  4  ounces  of  sugar  a  short  time 
before  the  usual  time  for  the  occurrence  of  fatigue  prevented  the  ap- 
pearance of  it.  Lemonade,  or  other  similar  refreshing  drink,  and 
chocolate  have  been  suggested  as  mediums  for  supplying  in  small 
doses  an  extra  amount  of  sugar  to  men  called  upon  to  perform 
extraordinary  muscular  labor.  The  application  of  these  results  to  the 
food  .of  soldiers  who  may  be  called  upon  for  extraordinary  exertion  in 
marching  or  fighting  is  very  evident.  Practical  tests  of  the  value  of 
sugar  in  preventing  or  delaying  fatigue,  made  in  both  the  German  and 
French  armies,  indicate  the  value  of  sugar  in  the  ration  when  the 
men  are  subjected  to  great  exertion. 

It  is  believed  that  more  decisive  results  may  be  obtained  by  tests 
with  men  and  animals  in  which  the  effects  of  given  quantities 
of  sugar  in  the  diet  are  compared  with  those  obtained  with  starch 
and  other  food  materials.      Such    experiments    have   been  made 

535 


SUGAK  AND  ITS  VALUE  AS  FOOD.  19 

under  the  auspices  of  this  department  with  men  iq  the  respiration 
calorimeter.  This  apparatus  makes  it  possible  to  measure  with 
great  accuracy  the  relation  between  the  material  consumed  and  the 
muscular  work  done.  In  experiments  planned  to  test  the  value  of 
carbohydratie  foods  as  a  source  of  energy  during  severe  muscular 
work,  the  subjects  were  able  to  include  350  grams,  or  about  three- 
quarters  of  a  pound,  of  cane  sugar  in  then*  daily  diet  without  any 
deleterious  effects.^ 

According  to  our  present  knowledge  the  value  of  sugar  as  a  food 
for  muscular  work  may  be  briefly  summarized  as  follows: 

Wlien  the  organism  is  adapted  to  the  digestion  of  starch,  and  there 
is  sufl&cient  time  for  its  utilization,  sugar  has  no  advantage  over 
starch  as  a  food  for  muscular  work. 

Id  small  quantities  and  in  not  too  concentrated  form  sugar  will 
take  the  place,  practically  weight  for  weight,  of  starch  as  a  food  for 
muscular  work,  barring  the  difference  in  energy  and  in  time  required 
to  digest  them,  sugar  having  the  advantage  in  these  respe.cts. 

It  furnishes  the  needed  carbohydrate  material  to  organisms  that 
have  httle  or  no  power  to  digest  starch.  Thus,  milk  sugar  is  part  of 
the  natural  f ootl  of  the  infant  whose  digestive  organs  are,  as  yet,  un- 
able to  convert  starch  into  an  assimilable  form. 

In  times  of  great  exertion  or  exhausting  labor,  the  rapidity  with 
which  it  is  assimilated  gives  sugar  certain  advantages  over  starch 
and  makes  it  prevent  fatigue. 

This  latter  quality,  which  renders  it  more  rapidly  available  for  mus- 
cular power,  may  account  for  the  fact  that  sugar  is  so  rehshed  by 
people  who  are  doing  muscular  work,  and  by  those  of  very  active 
habits,  such  as  children. 

The  American  farmer  ranks  high  among  agriculturists  as  a  rapid 
and  enduring  worker,  and  his  consumption  of  sweets  is  known  to  be 
very  large.  The  same  is  true  of  lumbermen  and  others  who  work  hard 
in  the  open  air;  sugar  and  sweet  cakes  are  favorite  foods  with  them. 
Dietary  studies  carried  on  in  the  winter  lumber  camps  of  Maine 
showed  that  largo  quantities  of  cookies,  cakes,  molasses,  and  sugar 
were  eaten,  sugar  of  aU  sorts  supplying  on  an  average  10  per  cent 
of  the  total  energy  of  the  diet. 

The  value  of  sugar  in  cold  climates,  whcr  foods  containing  starch 
are  not  available,  is  evident,  and  in  the  outfit  of  polar  expeditions 
sugar  is  now  given  an  important  place. 

Oriental  races  are  very  fond  of  sweets,  as  often  noted  l^y  travelers. 
Certain  forms  of  confectionery  are  very  popular  in  Turkey  and  other 
regions  of  the  East,  and  in  tropical  lands  the  consumption  of  dates, 
figs,  and  oth(;r  sweet  fruits  is  very  large.  In  a  discussion  ^  of  the 
food  of  the  natives  of  India  the  great  value  set  on  sweetmeats  or  sugar 

» U.  8.  Dept.  Agr.,  Omoe  Kxnt.  Htos.  BuL  17«.  »  Jour.  Trop.  Med.  [I/ondonl,  0  (1906),  p.  310. 

635 


20  SUGAE  AND  ITS  VALUE  AS  FOOD. 

by  the  Hindoo  population  of  all  classes  is  pointed  out.  Large  quan- 
tities of  brown  or  white  sugar  are  used  to  sweeten  the  boiled  milk, 
which  is  a  common  article  of  diet,  and  sugar  is  also  used  with  sour 
milk,  rice,  cheese,  and  other  foods.  It  has  also  been  said  that  the 
employer  who  wUl  not  furnish  the  native  laborers  with  the  large 
amounts  of  sugar  they  desire  in  their  daily  ration  must  expect  to  lose 
his  workmen. 

Certain  rowmg  clubs  in  Holland  have  reported  very  beneficial 
results  from  the  use  of  large  amounts  of  sugar  in  training. 

Pfliiger,  who  devoted  so  much  attention  to  glycogen  and  other 
carbohydrates,  says  that  undoubtedly  sugar  in  the  blood  is  heavily 
drawn  on  during  violent  exercise;  hence  the  longiug  for  it  in  a  form 
that  can  be  rapidly  assimilated. 

Its  use  by  mountain  climbers  is  well  known.  The  Swiss  guide  con- 
siders lump  sugar  and  highly  sweetened  chocolate  an  indispensable 
part  of  his  outfit. 

This  brief  summary  serves  to  show  the  use  which  is  made  of  sugar 
when  severe  work  is  performed,  and  some  of  the  experimental  data 
which  indicate  that  this  custom  is  justified. 

SUGAE  AS  A  FAT  FORMER. 

Sugar,  like  starch,  is  fattening;  that  is,  when  taken  in  excess  it 
may  be  transformed  into  fat  and  stored  as  reserve  material.  On  this 
account  physicians  commonly  advise  that  sugar  be  sparingly  used 
by  the  corpulent.  This  advice  is  given  because  sugar  in  the  form  of 
candy  or  other  sweets  is  often  taken  as  an  accessory  to  an  already 
abundant  diet. 

A  practical  illustration  of  the  use  of  sugar  as  a  fattening  food  is 
found  in  the  use  of  both  sugar  and  molasses  in  fattening  farm  animals, 
the  fat  so  produced  being  found  firm  and  of  good  quality.  In  sugar- 
producing  regions  it  is  a  common  constituent  of  the  rations  of  horsea 
and  mules,  and  it  is  fed  to  dairy  cattle  and  to  fattening  steers.  In 
Louisiana,  for  example,  it  is  the  usual  practice  to  feed  ''black  strap" 
molasses  to  plantation  horses  and  mules  at  the  rate  of  8  to  12  pounds 
per  head  per  day.  So  common  has  its  use  become  for  farm  animals 
in  general  that  many  mixed  rations  are  now  on  the  market  which 
contain  molasses  as  one  of  their  chief  constituents.  Sometimes  the 
materials  added  are  used  principally  to  absorb  the  molasses  and  make 
it  more  convenient  to  feed.  The  molasses,  of  course,  contains  prac- 
tically no  protein,  the  body-building  material,  and  frequently 
materials  are  mixed  with  it  which  are  rich  in  this  constituent  in  order 
that  the  mixed  feed  may  constitute  a  well-balanced  ration. 

SUGAR  AS  A  FLAVOR. 

In  addition  to  its  value  as  a  food,  sugar  is  important  in  the  diet  as  a 
flavor,  one  which  the  cook  could  not  easily  spare,  as  it  now  enters  into 

535 


SUGAR  AND  ITS  VALUE  AS  FOOD.  21 

a  great  variety  of  dishes.  Indeed  its  agreeable  flavor  has  always 
constituted  one  of  the  chief  reasons  for  its  use,  and  will  continue  to  do 
so,  even  though  we  make  use  of  the  abundance  of  relatively  cheap 
starchy  materials  we  possess  which  theoretically  may  readily  take  the 
place  of  sugar  as  a  food. 

In  some  dietary  studies  made  under  the  auspices  of  this  department 
with  a  club  of  students  at  the  University  of  Elaine,  an  investigation 
was  made  of  the  effect  of  supplying  a  liberal  amount  of  maple  sirup 
in  a  diet  which  contained  an  abundance  of  nutrients.  The  snup  was 
e^'idently  relished,  and  considerable  amounts  were  eaten.  However, 
there  was  not  a  corresponding  decrease  in  other  foods;  on  the 
contrary,  the  amount  of  flour  was  in  excess  of  the  amount  ordinarily 
consumed.  It  would  seem  that  the  maple  s:rup,  and  flour  in  the 
form  of  griddlecakes,  were  consumed  simply  on  account  of  their 
agreeable  flavor.  Provided  the  diet  contained  sufficient  nutrients  in 
the  first  place,  this  increase  was  not  desirable  on  the  ground  of  econ- 
omy, and  it  may  be  questioned  whether  it  was  desii*able  from  the 
standpoint  of  health.  When  a  similar  comparison  was  made  of  the 
addition  to  the  diet  of  liberal  quantities  of  milk,  which  has  a  much 
less  distinctive  flavor,  there  was  a  corresponding  decrease  in  the 
amount  of  other  foods  consumed.  This  would  indicate  that  much  of 
the  sugar  used  is  consumed  for  its  agreeable  flavor  and  not  because  it 
is  recognized  as  a  food  which  is  required  to  satisfy  body  needs. 

FOOD  VAI.TJE  OF  TABLE  SIBUPS  AND  MOLASSES. 

Sirups  of  various  kinds  and  molasses  have  always  been  used  to  a 
large  extent  in  the  United  States  as  articles  of  diet  and  for  cookery. 
There  are  several  forms  in  common  use.  Of  these,  maple  sirup,  which 
is  obtained  by  evaporating  tlie  sap  of  the  sugar  maple,  commands  the 
highest  price.  Cane  sirup  made  from  the  expressed  juice  of  the  sugar 
cane  is  another  important  sirup,  as  is  also  tlie  sirup  made  from 
sorghum  by  methods  very  much  lUvo  tliose  used  in  the  manufacture 
of  sirup  from  sugar  cane.  Very  much  used,  too,  are  the  homemade 
sirups  obtained  hj  boiling  sugar,  either  white  or  brown,  with  water. 
A  little  caramel  made  by  burning  sugar  in  a  frying  pan  and  dissolving 
it  in  water  may  be  added  to  the  sirup  to  give  both  color  and  flavor. 
Some  housekeepers  add  a  little  vinegar  to  homemade  sirup,  wliich 
imparts  a  flavor  and  inverts  more  or  less  of  the  sugar.  Sometimes 
water  in  which  several  corncobs  have  been  boiled  is  used  in  making 
homemade  sugar  sirups,  the  cobs  imparting  a  flavor  which  many 
relish  and  which  Is  said  to  suggest  maple.  In  Europe  a  simp  called 
"  whey  honey  "  is  made  by  boiling  doAvn,  with  sugar,  the  whey  drained 
from  rottage  (sour  milk)  rhccse  until  it  is  thick  as  honey,  the  propor- 
tions boing  1  pound  of  sugar  to  a  quart  of  whey.  This  has  a  pleasant 
and  distinctive  flavor. 

S3S 


22  SUGAR   AND   ITS   VALUE   AS   FOOD. 

An  interesting  example  of  the  use  of  molasses  in  quantity  is  fur- 
nished by  the  negroes  in  some  regions  of  the  Southern  States.  Dietary 
studies  in  the  Black  Belt  of  Alabama  showed  that  the  diet  was  made 
up  almost  entirely  of  molasses,  frequently  homemade,  com  meal,  and 
fat  pork. 

The  different  grades  of  molasses  obtained  as  by-products  in  the 
manufacture  of  sugar  from  sugar  cane  have  always  been  po'pular  as 
table  sirups  and  for  cookery.  Molasses  produced  by  the  open-kettle 
process  of  boiling  is  the  most  highly  appreciated,  and  for  a  long  time 
was  a  staple  article  for  both  purposes.  Generally  speaking,  it  can 
now  be  obtained  only  in  the  Southern  States  and  there  m  small 
quantities  only,  since  the  modern  process  of  sugar  making  has  prac- 
tically eliminated  this  open-kettle  molasses  from  the  market.  To 
supply  its  place,  the  manufacture  of  sirup  directly  from  the  sugar 
cane  and  without  the  separation  of  any  kind  of  sugar  has  come  to  be 
practiced  extensively  in  the  South,  particularly  in  Georgia,  Florida, 
Alabama,  Mississippi,  and  Louisiana.  According  to  an  early  publi- 
cation of  this  department,  ^'this  sirup  forms  a  delicious,  wholesome, 
and  valuable  condimental  food  substance,  the  use  of  which  is  rapidly 
extending;  and,  because  of  its  merits,  it  appears  destined  to  become 
a  very  important  food." 

For  some  reason  the  public  has  come  to  judge  sirup  largely  Oy  its 
color.  Many  prefer  a  dark  product  for  cooking,  partly  because  it 
colors  the  material  with  which  it  is  mixed,  and  partly  because  the 
dark  color  is  still  associated  in  their  minds  with  the  flavor  of  old- 
fashioned  molasses.  For  table  use,  however,  a  light-colored  sirup 
is  usually  preferred.  In  this  case  the  fact  has  apparently  been  over- 
looked that  if  properly  manufactured  good  sirup  must  possess  some 
color,  since  in  the  evaporation  of  the  sugar  juice  in  an  open  kettle  or 
pan  a  high  temperature  is  employed,  which  causes  an  inversion  of 
some  of  the  sugar,  and  also  has  a  tendency  to  produce  caramel  which 
imparts  a  color  to  the  sirup.  Though  a  light-colored  sirup  is  popular, 
a  brown  color  does  not  mean  that  the  sirup  is  not  of  good  quality. 

There  are  also  in  use  in  this  country  quantities  of  table  sirups 
which  are  simple  mixtures,  the  chief  ingredient  of  which  is  commer- 
cial glucose,  and  the  flavor  of  which  comes  very  largely  from  some 
of  the  sirups  and  molasses  mentioned  above.  In  certain  of  -these 
mixtures  which  owe  their  flavor  and  color  to  "refining  sirup,"  a 
by-product  of  the  sugar  refinery,  the  content  of  soluble  salts  is  large 
enough  to  impart  a  distinct  saline  flavor.  The  bone  black  used  in 
purifying  the  sugar  also  affects  the  flavor  of  "refining  sirup."  Since 
the  Federal  pure-food  law  was  enacted  such  mixtures  bear  a  label 
showing  the  constituents. 

Sugar-beet  molasses  is  not  used  for  table  purposes,  as  no  way  has 
been  found  to  free  it  commercially  from  objectionable  impurities. 

536 


SUGAR  AND  ITS  VALUE  AS  FOOD.  23 

NTJTEITIVE  VALUE  OF  SUGAR  CANE. 

The  entire  juice  of  the  ripened  sugar  cane  is,  of  course,  more  nearly 
a  complete  food  than  its  crystallized  sugar,  for  it  contains  other  con- 
stituents besides  carbohydrates.  It  is  elaborated  by  the  plant  as  a 
rich  food  for  building  up  young  leaves  and  buds.  In  sugar-producing 
countries  the  cane  is  regarded  as  a  staple  food  during  its  season. 
All  classes  of  people  chew  the  ripe  cane  freed  from  its  hard  rind, 
incredible  quantities  being  consumed  in  this  waj^.  Shiploads  are 
brought  daily  to  the  markets  of  Rio  Janeiro  and  West  Indian  towns. 
For  months  the  chief  food  of  the  negro  laborers  on  the  plantations  is 
said  to  be  the  sugar  cane,  and  they  are  seen  to  grow  strong  and  fat 
as  the  harvesting  season  advances,  although  they  may  begin  it  weak 
and  half-starved. 

PRACTICAL  USE  OF  SUGAR  IN  THE  ORDINARY  DIET. 

Sugar  was  formerly  regarded  as  a  condiment  and  valued  chiefly 
for  its  pleasant  taste,  but  its  food  value  has  been  fully  established 
and,  considering  the  immense  quantities  at  present  consumed,  it  is 
very  important  to  determine  the  extent  of  its  usefulness  in  dietaries. 
It  has  been  ascertained  that  in  large  numbers  of  well-to-do  families 
in  this  country  about  2  pounds  per  week  per  person  are  consumed. 
It  would  seem  that  this  amount,  or  about  one-fourth  of  a  pound 
daily,  taken  in  addition  to  other  food,  is  well  utilized  by  the  system. 
There  is  some  question  regarding  the  desirability  of  using  larger  quan- 
tities. The  use  of  sugar  it  would  seem  should  be  limited  in  two  ways: 
(1)  The  amount  consumed  should  not  be  greater  than  may  be  readily 
assimilated,  else  it  would  overload  the  stomach  and  bring  on  diges- 
tive disturbances  and  in  some  cases  might  produce  pathological  con- 
ditions in  the  excretory  organs;  and,  (2)  the  sugar  should  not  be  taken 
in  a  solution  or  other  form  so  concentrated  that  it  causes  a  burning 
sensation  or  other  digestive  disturbance  (see  p.  24).  The  question 
f'f  possible  permanent  injury  from  the  use  of  fairl}^  large  amounts  of 
ii;rar  seems  to  be  an  open  one,  and  certainly  the  extreme  views 
which  are  sometimes  found  in  popular  ^vritings  do  not  seem  to  be 
entertained  by  well-informed  physiologists,  the  conclusion  generally 
accepted  being  that  used  in  reasonable  amounts  sugar  is  both 
wholesome  and  nutritious. 

AMOUNT  AND  CONCENTRATION. 

Sugar  differs  greatly  from  starch  in  the  amount  that  can  be  properly 
used  in  the  system.  Starchy  foods,  such  as  potatoes,  bread,  etc.,  can  be 
digested  and  utilized  in  very  large  quantities.  As  much  as  600 
grams  (1 .3  pounds)  of  starch  per  day  may  be  digested  for  many  days 
without  difficulty.  This  amount  of  starch  is  contained  in  2.5  or  3 
pounds  of  bread,  or  in  6  or  7  pounds  of  potatoes.     Fewer  tests  have 

530 


24  SUGAR  AND  ITS  VALUE  AS  FOOD. 

been  made  regarding  the  maximum  amount  of  sugar  that  may  be 
used  by  the  system.  Vaughan  Harley  used  large  quantities  of  sugar 
in  some  of  his  experiments  on  himself,  but  400  grams  (nearly  a  pound) 
daily  for  some  time  very  much  affected  his  digestion. 

Since,  as  scientific  investigators  seem  agreed,  the  digestion  of  sugar 
is  relatively  so  rapid,  assimilation  and  storage  in  the  liver  can  not 
keep  pace  with  its  absorption  from  the  intestines  if  it  is  taken  in 
large  quantities.  In  this  case,  part  of  the  sugar  will  be  excreted 
unchanged.  Not  only  is  this  excess  of  sugar  wasted,  but  such  an 
unnatural  tax  on  the  excretory  organs,  if  constant  and  long  con- 
tinued, might  end  in  disease.  It  is  also  a  matter  of  common  obser- 
vation that  large  amounts  of  sugar  and  sweetened  food  are  apt  to  be 
accompanied  by  undue  fermentation  in  the  stomach  and  intestines. 
If  this  occurs  it  shows  that  the  quantity  of  sugar  eaten  is  too  great. 

In  this  regard,  investigators  have  pointed  out  that  sugar  bears  much 
the  same  relation  to  starch  that  peptone,  one  of  the  products  of  meat 
digestion,  does  to  meat.  Both  sugar  and  peptone  are  very  diffusible, 
and  thus  enter  rapidly  into  the  circulation,  strong  solutions  at  the 
same  time  irritating  the  mucous  membrane  with  which  they  come 
iato  contact  by  virtue  of  their  water-abstracting  power.  The  ''furry  " 
feeling  noticed  when  a  piece  of  hard  candy  is  held  in  the  mouth  for 
some  time  against  the  cheek  is  a  familiar  example  of  the  effect  pro- 
duced on  sensitive  membrane  by  a  concentrated  solution  of  sugar, 
which  is  undoubtedly  due  to  the  fact  that  equilibrium  of  density  is 
not  readily  established  between  the  liquid  of  the  two  sides  of  the 
membrane.  The  digestive  disturbances  noted  when  very  concen- 
trated solutions  of  sugar  or  other  substances  are  taken  into  the 
stomach  are  attributed  to  similar  causes;  that  is,  to  differences  in  the 
density  of  solutions  on  the  two  sides  of  the  livLag  membrane. 

Doubtless  because  sugar  is  commonly  excluded  from  the  diet  of 
diabetics  the  statement  has  been  made  that  eating  sugar  is  the  cause 
of  this  disease,  which  of  course  does  not  follow.  Such  an  opinion  is 
not  entertained  by  physiologists,  as  is  apparent  from  the  statement 
in  a  recent  report  ^  of  the  Connecticut  State  Agricultural  Experi- 
ment Station,  which  shows  the  fallacy  of  such  a  belief.  That  sugar, 
honey,  sirup,  etc.,  "produce  diabetes"  would,  according  to  the 
report,  be  "startling  if  true." 

It  is  sometimes  said  that  sugar  produces  gout.  There  seems  to  be 
no  proof  of  this  theory. 

Sugar  seems  iU  adapted  to  the  sick,  except  when  used  in  very  small 
quantities  as  a  flavor.  Jacobi^  remarks  that  the  absorption  of 
sugar  is  slower  by  sick  than  by  healthy  children,  and  that  in  such 


535 


1  Connecticut  State  Sta.  Rpt.  1911,  pt.  2,  p.  161. 

2  Therapeutics  of  Infancy  and  Childhood.    Philadelphia,  1896,  p.  16. 


SUGAR  AND  ITS  VALUE  AS  FOOD.  25 

cases  only  a  little  should  be  given  and  never  in  concentrated  form. 
He  also  states  that  the  conversion  of  milk  sugar  into  lactic  acid 
takes  place  very  rapidly,  while  cane  sugar  is  not  so  readily  trans- 
formed, and  accordingly  he  insists  that  the  latter  be  added  to  the 
food  of  infants  and  children. 

When  any  bad  effects  can  be  ascribed  to  sugar  they  are  usually  due 
to  its  use  in  larger  quantities  than  the  3  or  4  ounces  a  day  which  seem 
to  be  digested  by  the  healthy  adult  without  difficulty.  The  conclusion 
to  be  drawn  from  such  experimental  work  as  that  referred  to  is  that 
overeating  with  sugar  is  to  be  avoided,  not,  as  has  sometimes  been 
stated,  that  sugar  is  other  than  a  useful  foodstuff. 

The  statement  is  sometimes  made  that  sugar  is  unwholsome  because 
it  has  been  separated  from  the  plant  and  is  therefore  "artificial." 
Like  a  host  of  other  statements  of  similar  popular  origin,  this  is  based 
on  belief  rather  than  experience  and  evidence  and  is  not  the  view 
generally  held.  Bimge^  has  called  attention  to  the  lack  of  calcium 
(lime)  and  iron  in  sugar  as  compared  with  honey  and  sweet  fruits. 
His  contention  that  this  might  be  a  possible  soiu"ce  of  danger  does 
not  seem  probable  when  one  considers  the  varied  character  of  our  diet 
and  its  abundant  supply  of  fruits  and  vegetables,  milk  products,  and 
other  foods  which  contain  calcium  and  iron.  The  object  sought  is,  of 
course,  to  supply  in  the  diet  all  the  substances  which  the  body  needs, 
and  if  this  is  done  by  the  foods  as  a  whole,  the  possible  lack  of  a  con- 
stituent or  constituents  in  some  single  food  which  forms  a  part  of  the 
diet  is  not  of  importance.  If  for  any  reason  calcium  is  lacking  in 
the  diet,  the  deficiency  may  be  easily  made  good  by  increasiug  the 
amomit  of  milk  and  milk  products.  Similarly,  iron  may  be  increased, 
if  this  is  desirable,  by  taking  more  fruits,  green  vegetables,  and  the 
coarser  milling  products  of  the  cereal  grains,  foods  which  are  within 
the  reach  of  practically  everyone. 

It  will  be  noticed  that  sugar  as  it  exists  in  nature — e.  g.,  in  the 
sugar  cane,  in  milk,  and  in  most  fruits — is  not  higlily  concentrated. 
In  mUk  it  constitutes  from  4  to  6  per  cent.  It  would  seem  that  the 
animal  organism  is  best  adapted  to  the  utilization  of  food  principles 
in  the  somewhat  dilute  or  bulky  form  in  wliich  they  occur  in  the 
commonly  accepted  foods — protein  as  found  in  meat,  mUk,  etc., 
starch  in  grains,  and  sugar  in  small  quantities  at  a  time  as  found  in 
vegetable  juices  and  milk  and  in  combination  with  other  foods — and 
that  it  does  not  readUy  accept  unlimited  amounts  of  chemically  iso- 
lated and, purified  food  princii)les.  Most  of  the  statements  wiiich 
have  been  made  regarding  tlio  amounts  of  sugar  which  are  well  toler- 
ated depend  upon  evidence  obtained  in  experiments  in  which  the  sugar 

>  Ztscbr.  BioL,  61  (1901),  p.  IfiS. 
68C 


26  SUGAK  AND  ITS  VALUE   AS   FOOD. 

was  used  dissolved  in  liquid,  as  in  tea,  coffee,  or  some  similar  way, 

or  from  experience  of  the  results  which  sometimes  follow  when  a 

large  quantity  of  sirup  or  candy  or  some  similar  product  rich  in  sugar 

is  taken.     How  far  the  conclusions  drawn  would  apply  to  sugar  taken 

in  cake,  pastry,  custards,  and  other  cooked  foods  can  not  be  stated 

definitely,  as  few  tests  have  been  made  upon  the  digestibility  of  such 

foods.     With  the  exception  of  thick  preserves  and  some  similar  foods, 

in  which  sugar  is  used  as  a  preservative  as  well  as  a  flavor,  most 

cakes,  custards,  and  other  foods  flavored  with  sugar  contain  it  in 

moderate  amounts,  which  means  that  the  sugar  is  diluted  or  extended 

by  a  considerable  quantity  of  other  material.     In  this  connection  it 

may  be  said  that  it  is  the  usual  custom  to  take  sugar  in  dilute  form, 

as,  for  instance,  when  we  add  it  to  tea  or  coffee,  sprinkle  it  on  fruit, 

add  it  with  milk  or  cream  to  breakfast  cereals,  or  use  it  in  other  similar 

ways. 

SUGAR  AND  THE  TEETH. 

It  is  often  said  that  sugar  is  harmful  to  the  teeth,  but  the  facts 
seem  to  be  as  follows:  According  to  the  theory  universally  accepted, 
the  decay  of  the  teeth,  technically  called  caries,  is  caused  by  bacteria, 
such  as  are  found  in  every  mouth,  entering  the  soft  portions  of  the 
teeth  through  defects  in  the  hard  outer  covering.  If  acid  is  present 
in  the  mouth,  and  especially  in  the  interstices  of  the  teeth,  it  tends 
to  eat  into  the  enamel  and  thus  provide  an  entrance  for  the  caries- 
producing  bacteria.  Ordinarily,  saliva  is  alkahne  and  protects  the 
teeth  against  this  danger,  but  when  it  is  in  contact  with  sugar  or 
starch,  acid  is  produced,  hence  a  carbohydrate  material  lodged  upon 
the  teeth  may  be  the  indirect  cause  of  caries.  Some  authorities  hold 
that  certain  forms  of  sugar  cause  the  flow  of  a  less  alkaline  saliva, 
but  this  point  is  not  fully  estabhshed.  In  general,  it  is  believed 
that  starch  is  just  as  dangerous  as  sugar,  and  that  the  form  and  man- 
ner in  which  the  material  is  eaten  is  a  more  important  consideration 
than  its  exact  chemical  structure.  Soft  foods  are  especially  hkely  to 
cause  trouble^  both  because  bits  of  them  may  remain  on  the  teeth 
where  they  form  "plaques"  which  are  centers  of  bacterial  action  so 
long  as  they  remain,  and  because  they  are  swallowed  without  much 
chewing  and  thus  do  not  rub  the  food  "plaques"  or  other  deposits 
from  the  teeth.  Modern  speciahsts  consider  that  the  cleansing  action 
of  proper  mastication  is  as  important  for  the  preservation  of  the 
teeth  as  the  regular  use  of  a  toothbrush,  important  as  this  last  is. 
Any  soft  carbohydrate  food  eaten  alone  is  much  more  likely  to  leave 
a  deposit  on  the  teeth  than  if  it  is  eaten  in  combination  with  other 
foods.  If  candies  are  eaten  by  themselves,  they  are  more  likely  to 
cause  the  development  of  acid  in  the  mouth  than  if  they  are  taken 

535 


SUGAR  AND  ITS  VALUE  AS  FOOD.  27 

during  a  meal.  Some  physicians  advise  finishing  the  meal  with  acid 
fruit  for  the  sake  of  lessening  the  chances  of  carbohydrate  material 
clinging  to  the  teeth.  While  soft  foods  may  possibly  cause  trouble, 
the  hard  ones  may  also  be  dangerous,  especially  to  diseased  teeth, 
as  the  effort  to  crush  them  may  tend  to  increase  flaws  in  the  enamel. 
Such  things  as  hard  crusty  food,  hard  candies  such  as  lemon  drops, 
stick  candy,  etc.,  may  be  dangerous  in  this  respect,  though  invest!-' 
gations  by  G.  V.  Black  ^  on  the  crushing  force  of  the  teeth  have 
proved  that  sound  teeth  are  capable  of  crushing  much  harder  sub- 
stances than  these  without  injury. 

EFFECT  OF  EXERCISE  ON  THE  AMOUNT  OF  SUGAR  WHICH  MAY  BE 

EATEN. 

The  amount  of  sugar  that  may  be  eaten  without  bad  effects  depends 
much  on  the  amount  of  exercise  taken.  It  has  been  observed  that 
a  man  doing  hard  work  in  the  open  air  can  easily  assimilate  large 
quantities  of  sugar,  while  the  same  quantity  would  cause  indigestion 
if  eaten  when  Uving  indoors  and  taking  httle  exercise.  This  is  what 
might  be  expected,  as  the  active  outdoor  hfe  means  much  physical 
work  or  exercise,  either  of  which  involves  much  muscular  energy. 
Sugar,  as  has  been  pointed  out,  is  a  valuable  energy-yielding  food. 

SUGAR  IN  COOKING,  PRESERVING,  AND  CONFECTIONERY. 

Sugar  is  used  in  cookery,  in  the  manufacture  of  confectionery, 
which  is  almost  entirely  sugar,  and  as  an  addition  to  a  great  variety 
of  foods.  It  is  almost  always  used  with  cooked  fruit,  cakes,  pastry, 
and,  in  general,  food  made  with  eggs  and  flour,  and  very  rarely  with 
meat  dishes  in  modern  cookery,  though  often  added  in  earher  times, 
as  old  recipe  books  show,  to  meat  pies,  which  were  heavily  seasoned 
with  sugar  and  spice.  Mince  pie  is  one  of  the  very  few  surviving 
representatives  of  such  foods.  Sugar  and  fat  are  often  cooked 
together,  and  many "  foods,  butter-scotch  for  example,  owe  their 
pleasing  flavor  to  this  combination.  Sugar  and  suet  are  often  used, 
as  in  puddings,  but  leas  often  now  than  formerly. 

Sugar  added  in  cakes  and  pastry  affects  the  texture  as  well  as  the 
composition  and  flavor,  as  any  cook  knows.  A  special  form  of  cookery 
is  the  making  of  preserves,  jams,  jellies,  etc.,  and  in  those  sugar  in 
thick,  heavy  solution  not  only  adds  to  the  palatability  and  character  of 
the  flavor,  but  it  also  acts  as  a  preservative.  On  the  contrary,  thin 
solutions  of  sugar  alone  or  with  fruit  juices,  etc.,  are  very  readily  sub- 
ject to  dec<^miposition  by  microorganisms.  Hence,  in  order  that  it 
may  act  as  a  preservative,  a  solution  of  sugar  must  be  concentrated. 

Without  doubt  more  sugar  is  used  in  cookery  and  in  making  jams, 

»  A  work  on  operative  dentistry,  Chicago  and  I/ondon,  1008,  Vol.  I,  p.  101. 


28  SUGAE  AND  ITS  VALUE  AS  POOD. 

jellies,  and  preserves,  and  in  making  confectionery  (which  is  a  special 
form  of  cookery)  than  in  any  other  way.  In  general  it  may  be  said 
that  for  ordinary  cakes  the  proportion  of  sugar  is  not  usually  greater 
than  one  part  by  measure  to  two  parts  of  flour,  and  that  too  much 
sugar  should  not  be  used  in  making  puddings,  cakes,  etc.,  since 
oversweetening,  like  other  forms  of  overflavoring,  is  regarded  as  a 
mark  of  unskilled  cookery.  In  the  case  of  canned  fruits  a  common 
proportion  is  one  part  of  sugar  to  two  parts  of  fruit  by  weight;  for 
preserves,  equal  parts  of  sugar  and  fruit;  and  for  jellies,  three- 
quarters  to  one  part  by  weight  of  sugar  to  one  part  of  juice. 

Detailed  recipes  for  making  preserves,  jellies,  and  similar  articles 
are  given  in  earher  buUetias  ^  in  this  series.  Directions  for  making 
cakes,  pies,  puddings,  and  other  such  dishes  in  which  sugar  is  an 
important  part  can  be  found  in  cookbooks  and  similar  publications. 

Candy  of  the  better  grade  is  very  largely  made  up  of  sugar,  with 
the  addition  of  various  coloring  matters  and  flavors,  nuts,  fruit,  etc., 
and  sometimes  fat,  starch,  and  commercial  glucose.  The  food  value  of 
most  candies  may  be  expressed  by  the  amount  of  the  sugar  contaiaed 
(72  to  96  per  cent),  but  as  regards  wholesomeness  the  other  in- 
gredients must  be  taken  into  account.  The  coloring  matters  used  in 
cheap  candies  are  nearly  all  compounds  of  anilin  or  other  coal-tar 
products,  some  of  which  are  thought  to  be  harmless.  Some  of  the 
coloring  matters  and  flavors  used,  however,  have  been  shown  to  be 
harmful.  Ordinary  caution  would  suggest  that  children,  at  least, 
be  allowed  to  partake  very  sparingly  of  such  unknown  compounds. 
Two  hundred  and  fifty  samples  of  cheap  candy  examined  by  the 
Bureau  of  Chemistry  of  this  department  a  few  years  ago  were  found 
to  be  made  up  largely  of  commercial  glucose  with  a  little  sugar  and 
starch.  Candies  are  often  exposed  to  the  dust  and  dirt  in  stores  and 
booths,  taken  out  of  jars  and  boxes  by  dirty  hands,  or  weighed  in 
scales  of  questionable  cleanHness.  Dangerous  microorganisms  such 
as  are  frequently  present  in  dust  may  thus  lodge  on  them  and  be 
eaten  with  the  candy.  Cleanliness  in  the  marketing  of  this  class  of 
goods  is  just  as  necessary  as  in  the  case  of  fruits  or  vegetables,  per- 
haps more  so,  as  the  others  can  be  washed  if  they  are  to  be  eaten 
raw,  and  candies  would  not  be  washed. 

Studies  recently  made  in  Pennsylvania  ^  show  that  while  there  has 
been  marked  improvement  in  the  quality  of  cheap  candies  during 
the  last  few  years,  there  is  room  for  still  greater  improvement  in  the 
form  of  these  candies  and  the  method  of  marketing  them.  Many  are 
made  in  the  form  of  whistles,  marbles,  belts,  and  necklaces,  which 
the  children  often  play  with  and  which  become  very  dirty  before  they 

1  U.  S.  Dept.  Agr.,  Farmers'  Bills.  203,  Canned  Fruit,  Preserves,  and  Jellies— Household  Methods  of 
Preparation;  359,  Canning  Vegetables  in  the  Home;  and  426,  Canning  Peaches  on  the  Farm. 

2  Pennsylvania  Dent.  A.gr.,  Dairy  and  Food  Div.  Bui.  216. 

535 


SUGAB  AND  ITS  VALUE  AS  FOOD.  29 

are  eaten.     The  desirabilit}'  of  having  candies  wrapped  or  at  least 
protected  from  dust  and  dirt  while  exposed  for  sale  is  evident. 

The  custom  of  marketing  candies  wrapped  or  of  packing  them  in 
boxes,  etc.,  at  the  factory  is  a  growing  one,  particularly  with  the  more 
expensive  sorts,  and  is  certainly  a  measure  which  makes  for  cleanli- 
ness. With  respect  to  the  candies  themselves,  manufacturers  who 
realize  their  responsibility  endeavor  to  insure  sanitary  conditions  in 
their  manufactories.  In  a  number  of  States  the  candy  factories,  like 
hke  other  food  manufactories,  are  inspected  under  State  auspices. 

SUGAB  IN  FRUITS. 

A  large  number  of  studies  of  fruits  and  fruit  products  by  the  Cali- 
fornia experiment  station  indicate  that  the  food  value  of  fruits  is 
largely  due  to  the  various  sugars  they  contain,  the  ones  most  com- 
monly found  being  cane  sugar,  grape  sugar  or  dextrose,  and  fruit 
sugar  or  levulose,  the  last  two  usually  present  together  in  equal 
quantities,  in  which  case  they  are  collectively  knoAvn  as  invert  sugar, 
though  sometimes  not  in  equal  quantities,  in  which  case  they  are 
called  reducing  sugar. 

The  stage  of^rowth  and  the  degree  of  ripeness  have  a  very  decided 
effect  on  the  kind  and  amount  of  sugar  present  in  fruits,  and  it  is 
therefore  difficult  to  give  average  figures  which  will  f ahly  represent 
the  quantities  present.  According  to  figures  published  several  yeara 
ago,  invert  sugar  ranges  from  about  2  per  cent  in  large  early  apricots 
to  15  per  cent  in  grapes  and  a  variety  of  sweet  cherries,  while  straw- 
berries, gooseberries,  raspberries,  and  apples  contain  about  half  the 
latter  quantity.  The  cane  sugar  ranges  from  less  than  1  per  cent  in 
lemons  to  14  per  cent  in  a  variety  of  plums.  Ripe  bananas  were  also 
found  to  contain  a  fairly  high  percentage,  namely,  11  per  cent. 

Dried  fruits,  like  figs,  dates,  and  raisins,  which  have  been  con- 
centrated by  evaporation,  naturally  contain  much  greater  propor- 
tions of  sugar  than  fresh  fruits,  the  amount  of  levulose  reported  bcmg 
•-Mmctimes  over  50  per  cent.     The  use  of  such  sweet  fruits  for  swoet- 

ling  cooked  breakfast  cereals  and  other  dishes  is  by  no  means  un- 
(oinmon.  The  question  of  the  sugar  content  of  fresh  fruits  and  dried 
f  1  uits  and  their  value  as  food  has  been  discussed  in  earlier  })ublications.* 

Jams,  jellies,  and  similar  products  almost  always  contain  added 
sugar,  and  hence  their  nutritive  vahn?  may  ])o  considerable.  Home- 
made jams  are  often  cooked  l(jngor  than  the  commercial  ones,  and 
tlieroforc  may  contain  a  larger  proportion  of  invert  sugar.  On  the 
other  hand,  commercial  brands  ar(i  often  made  with  glucose,  but  the 
law  requires  that  the  fact  bo  stated  on  the  label,  along  with  the  i)ro- 
portions  of  chemical  preservatives,  etc.,  if  present.     (See  also  p.  12.) 

'  U.  8.  Dcpt.  Art.,  rarm'-n'  IJul.  283,  Uao  of  FruJt  as  Food;  V.  B.  Dopt.  Agr.,  Yearbook  »»2,  p.  606, 
Haislaa,  Fign,  and  Otbcr  J;rli;<i  Kruita,  and  TtiBii-  Uiesiut  Food. 


30  SUGAE  AND  ITS  VALUE  AS  FOOD. 

SUGAE  m  THE  DIETAEIES  OF  CHILDEEN. 

The  amotint  of  sugar  to  b©  given  children  and  in  what  form  is  a 
question  of  much  importance.  Sugar  would  seem  to  be  a  food  espe- 
cially adapted  to  children  because  of  their  great  activity.  The  rela- 
tively smaU  body  of  the  child  loses  more  heat  from  the  skin  for  every 
pound  of  body  weight  than  does  the  larger  person,  and  children,  on 
this  account  and  because  of  their  active  life,  require  proportionally 
more  heat  units  in  their  food  than  do  adults. 

Fat,  especially  fat  meat,  which  could  readily  supply  this  need,  is 
often  dishked  by  the  child,  and  his  rehsh  for  all  kinds  of  sweets  has 
doubtless  a  physiological  basis.  It  is  to  be  remembered,  however, 
that  before  the  introduction  of  cane  sugar  as  we  now  know  it  count- 
less generations  of  children  had  been  reared  without  its  help.  The 
digestibility  of  sugar  and  sweetened  foods  for  children  and  their  in- 
fluence on  the  appetite  for  other  foods  must  decide  to  what  extent 
sugar  is  to  replace  starch  in  the  dietary  and  how  far  it  may  be  safely 
used  as  a  flavor. 

Until  a  child's  stomach  is  capable  of  digesting  starch  the  needed 
carbohydrate  is  furnished  in  the  sugar  of  milk,  the  child  a  year  old 
who  drinks  2  quarts  of  milk  a  day  taking  in  this  way  about  3  ounces 
of  milk  sugar.  As  the  stomach  becomes  abld  to  digest  starch  the 
child  is  less  and  less  dependent  on  the  sugar  of  milk,  replacing  it  with 
the  ca.rbohydrates  of  vegetable  origin,  while  the  protein  and  fat  found 
in  eggs,  meat,  breakfast  cereals,  and  bread  and  butter  take  the  place  of 
those  constituents  that  were  at  first  exclusively  f7arnished  in.  milk. 
Milk,  however,  remains  throughout  childhood  a  valuable  source  of 
all  these  food  principles. 

The  fact  that  sugar  has  a  high  food  value  is  not  the  only  point  to 
be  considered.  The  child  will  easily  obtain  the  needed  carbohydrates 
in  other  forms,  and  will  thrive  if  its  digestion  remains  sound  and  its 
relish  for  wholesome  food  unimpaired.  For  instance,  one  often  hears 
it  said  that  a  certain  chUd  does  not  relish  milk.  In  such  cases  it 
might  be  found  that  the  child's  appetite,  being  sated  by  sugar  in 
other  foods,  is  no  longer  attracted  by  the  mild  sweetness  of  fresh 
milk,  delicious  as  it  is  to  the  unspoiled  palate.  It  would  be  well, 
perhaps,  in  this  instance  to  cut  down  the  allowance  of  sugar  in  the 
hope  of  restoring  the  taste  for  so  invaluable  a  food  as  milk.  Many 
believe  that  the  infant,  even  in  its  second  year,  should  not  be  per- 
mitted to  taste  sweets,  in  order  to  prevent  perversion  of  the  appetite. 
Even  much  later,  for  the  same  reason,  the  introduction  of  large 
amounts  of  sugar  into  the  daily  food  of  children  is  to  be  carefully 
considered.  Children  do  not  require  a  variety  of  flavors  to  stimulate 
the  appetite,  but  the  taste  is  easily  perverted  and  the  restoration  of 
a  normal  appetite  is  difficult.     Those  who  have  studied  the  food 

535 


SUGAE  AND  ITS   VALUE   AS   FOOD.  31 

habits  of  children  seem  to  agree  that  sugar  should  from  the  very 
first  be  withheld  from  the  dish  that  forms  the  staple  food  of  the 
child — that  is,  the  mush  or  porridge  of  oatmeal  or  other  cereal. 
This  article  of  diet,  eaten  only  with  milk  or  cream,  falls  into  the  same 
class  as  bread  and  milk  and  forms  the  simple,  wholesome  basis  of  a 
meal.  The  sugar  given  the  child  is  better  furnished  in  the  occasional 
simple  pudding,  in  the  lump  of  sugar,  or  homemade  candy,  not  that 
its  food  value  is  better  utilized,  but  that  the  whole  diet  of  the  child 
1  thus  made  more  wholesome.  In  sweet  fruits,  fully  ripened,  the  child 
finds  sugar  in  a  healthful  form,  and  they  should  be  freely  furnished. 

COMPARATIVE  COST  OF  SUGAR  AS  FOOD. 

Ten  cents'  worth  of  sugar  at  6  cents  per  pound  would  furnish 
2,920  calories  of  energy.  At  6  or  7  cents  per  pound  sugar  compares 
favorably  with  other  foods  as  a  source  of  energy,  although  it  is  more 
expensive  than  starch  in  the  form  of  such  cereal  foods  as  wheat  flour, 
corn  meal,  and  oatmeal,  which  contain  65  to  80  per  cent  of  carbo- 
hydrates and,  in  addition,  10  to  14  per  cent  of  protein,  and  cost  from 
2.5  to  4  cents  per  pound.  Judging  from  the  results  of  many  dietary 
studies,  the  average  cost  of  sugar  in  the  daily  ration  is  about  2  cents, 
and,  compared  with  some  other  common  foods,  sugar  is  not  an  ex- 
pensive item  in  the  dietary. 

GENERAL  CONCLUSIONS. 

One  may  say  in  general  that  the  wholesomeness  of  sweetened  foods 
and  their  utilization  by  the  system  is  largely  a  question  of  quantity 
and  concentration.  For  instance,  a  simple  pudding  flavored  with 
sugar  rather  than  heavily  sweetened  is  considered  easy  of  digestion, 
'  it  when  more  sugar  is  used,  with  the  addition  of  eggs  and  fat,  we 
ve  as  the  result  highly  concentrated  forms  of  food,  which  can  be 
ten  with  advantage  only  in  moderate  quantities  and  which  are 
I  ntirely  unsuited  to  children  and  invalids. 

It  is  true  that  the  harvester,  lumberman,  and  others  who  do  hard 

)rk  in  the  open  air  consume  great  amounts  of  food  containing  con- 

:  iderable  quantities  of  sugar,  such  as  pie  and  doughnuts,  and  appar- 

<  iitly  with  impunity;  but  it  is  equally  true  that  people  livuig  an 
indoor  life  find  that  undue  amounts  of  pie,  cake,  and  pudding,  with 
}ii;^dUy  sweetened  preserved  fruit,   and  sugar  in  large  amounts  on 

<  ooked  cereals,  almost  always  bring  indigestion  sooner  or  later. 

From  a  gastronomic  point  of  view  it  would  seem  also  that  in  the 
American  cuisine  sugar  is  used  with  too  many  kinds  of  food,  with  a 
consequent  loss  of  variety  and  piquancy  of  flavor  in  the  difrcrciit 
dishes.  The  nutty  flavor  of  grains  and  the  natural  taste  of  mild  fruits 
are  very  often  concealed  by  the  addition  of  largo  quantities  of  sugar. 

636 


^2  SUGAE  AND   ITS   VALUE   AS  FOOD. 

In  the  diot  of  the  undernourished  larger  amounts  of  sugar  would 
doubtless  help  to  supply  adequate  nutrition.  This  point  is  often 
urged  by  European  hygienists.  In  the  food  of  the  well-to-do  it  is 
often  the  case,  however,  that  starch  is  not  dimuiished  in  proportion 
as  sugar  is  added.  That  sugar,  on  account  of  its  agreeable  flavor, 
furnishes  a  temptation  to  take  more  carbohydrate  food  than  the 
system  needs  can  not  be  denied.  The  vigor  of  digestion  and  muscular 
activity  in  each  particular  case  would  seem  to  suggest  the  limit,  A 
lump  of  sugar  represents  about  as  much  nutriment  as  an  ounce  of 
potato,  bul},  while  the  potato  will  be  eaten  only  because  hunger 
prompts,  the  sugar,  because  of  its  taste,  may  be  taken  when  the 
appetite  has  been  fully  satisfied. 

Sugar  is  a  useful  and  valuable  food.  It  must,  however,  be  remem- 
bered that  it  is  a  concentrated  food,  and  therefore  should  be  eaten 
in  moderate  quantities.  Further,  like  other  concentrated  foods, 
sugar  seems  best  fitted  for  assimilation  by  the  body  when  supplied 
with  other  materials  which  dilute  it  or  give  it  the  necessary  bulk. 

Persons  of  active  habits  and  good  digestion  will  add  sugar  to  their 
food  almost  at  pleasure  without  inconvenience,  while  those  of  seden- 
tary life,  of  delicate  digestion,  or  with  a  tendency  to  corpulency  would 
do  better  to  use  sugar  very  moderately.  It  is  generally  assumed  that 
4  or  5  ounces  of  sugar  per  day  is  as  much  as  it  is  well  for  the  average 
adult  to  eat  under  ordinary  conditions. 

(A  list  giving  the  titles  of  all  Farmers'  BuUetms  available  for  dis- 
tribution will  be  sent  free  upon  application  to  a  Member  of  Congress 
or  the  Secretary  of  Agriculture.) 

535 

o 


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Sugar  and  its  value  as  food. 


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